##### Department of Mathematics,

University of California San Diego

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### Adjoint P-orbits for orthogonal groups

## Karin Baur

#### ETH Zurich

## Representation Theory Seminar

##### Abstract:

Consider a parabolic subgroup of a reductive group G. By a theorem of Richardson (1974), the adjoint action of P on its nilpotent radical has an open dense orbit. In general, there is an infinite family of orbits, so the description of the P-orbits is a ``wild'' problem.In type A there exists a translation of this problem into a question of representation-type of a category of representations of an algebra due to Hille and R\"ohrle (1999). In this talk I will describe their approach and explain how it can be extended to deal with parabolic subgroups of orthognal groups.

Host: Nolan Wallach

### January 20, 2009

### 1:00 PM

### AP&M 7321

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